Telecommunication cable particularly paired cable with improved relative crosstalk properties for certain pairs

ABSTRACT

A paired or quadded telecommunication cable have conductors arranged in groups. One pair or quad within each group does not change place and is shielded by the other pairs or quads within the group resulting in a high relative freedom of crosstalk.

United States Patent [191 Karlstedt June 28, 1974 TELECOMMUNICATIONCABLE,

PARTICULARLY PAIRED CABLE WITH IMPROVED RELATIVE CROSSTALK PROPERTIESFOR CERTAIN PAIRS [75] Inventor: Sten Lennart Karlstedt, Stockholm,

Sweden [73] Assignee: Telefonaktieboiaget L M Ericsson,

Stockholm, Sweden [22] Filed: Feb. 20, 1973 [21] Appl. No: 334,137

[30] Foreign Application Priority Data Mar. 2, 1972 Sweden 2654/72 [52]US. Cl. 174/113 R, 174/34, 174/35 [51] Int. Cl. H0lb 11/10 [58] Field ofSearch 174/34, 33, 35 R, 113 R,

[56] References Cited UNITED STATES PATENTS 2,014,214 9/1935 Smith174/34 2,845,473 7/1958 Doherty 174/33 X 3,105,108 9/1963 Brazee 174/113R 3,433,890 3/1969 Gabriel 174/113 R Primary Examiner-E. A. GoldbergAttorney, Agent, or Firm-Harte, Baxley and Spiccens [57] ABSTRACT Apaired or quadded telecommunication cable have conductors arranged ingroups. One pair or quad within each group does not change place and isshielded by the other pairs or quads within the group resulting in ahigh relative freedom of crosstalk.

1 Claim, 1 Drawing Figure 1 TELECOMMUNICATION CABLE, PARTICULARLY PAIREDCABLE WITH I IMPROVED RELATIVE CROSSTALK PROPERTIES FOR CERTAIN PAIRSThe present invention relates to a telecommunication cable, particularlya paired or a quadded cable, for transmission of telecommunicationsignals, comprising a number of insulated conductors arranged as pairsor quads in groups or sub groups, wherein the pairs or quads changingtheir relative positions systematically or at random.

Cables of the kind under discussion are manufactured for reducing andcompensating the crosstalk between conductor pairs or quads. Very goodresults have been achieved with cables of this kind and the crosstalkbetween arbitrarily chosen pair or quad combinations have been reducedto an acceptable level, as far as speech transmission is concerned.However, conductors intended for telephone calls are to an increasinglylarger extent being used for transmission of other kinds of signals,e.g. signals for picture telephone, PCM- systems and data communication.In such connections the requirements for freedom of relative crosstalkare particularly high.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE represents the cable incross section.

The present invention relates to a cable in which a number of pairs orquads have a very high relative freedom of crosstalk which is achievedby practing the invention as defined by the appended claim.

An embodiment of the invention will be more fully described accompanyingwith, reference to the drawing, which in cross section, shows atelecommunication cable ll comprising ten groups 2, of which each one inturn comprises ten conductor pairs 3. In known embodiments these tenconductor pairs change places systematically or at random in such a waythat the crosstalk between an arbitrarily chosen conductor pair and eachone of the other conductor pairs is almost constant. In the shownembodiment there are eight conductor pairs in the periphery of thegroup, while two conductor pairs form the core of the group. Accordingto the invention one or several pairs 4 in a number of groups areexcepted from the relative changing of places and maintain their placesalong the whole length of thecable. For achieving the bestpossible'relative crosstalk freedom between the pairs 4 they are placedin the centre of the respective group. The other com ductor pairs thenform a shield around the chosen pairs; and shield also protects thesepairs from external disturbances. This is particularly advantageous inconnection with aerial cables in which the surface layers are moreexposed to external disturbances than the inner layers.

I claim:

1. A telecommunication cable comprising a plurality of telecommunicationsignal conductors wherein each of said telecommunication signalconductors comprises at least two insulated wires, said plurality beingarranged into at least two groups, within each group thetelecommunication signal conductors thereof being arranged to surroundat least one of the telecommunication signal conductors while changingrelative positions with respect to each other except for said onetelecommunication signal conductor whose position remains constant alongthe length of the cable.

1. A telecommunication cable comprising a plurality of telecommunicationsignal conductors wherein each of said telecommunication signalconductors comprises at least two insulated wires, said plurality beingarranged into at least two groups, within each group thetelecommunication signal conductors thereof being arranged to surroundat least one of the telecommunication signal conductors while changingrelative positions with respect to each other except for said onetelecommunication signal conductor whose position remains constant alongthe length of the cable.